Whether you’re scheduling a meeting with a client in Dubai, calling family back home, or working with a remote team across three continents, time zone conversions are a daily necessity. But time zones can be confusing — daylight saving, UTC offsets, and half-hour zones all add complexity.
This guide covers everything you need to know about time zones: how they work, conversion charts for major cities, daylight saving gotchas, and tips for managing time across global teams.
How Time Zones Work
The Basics
The Earth is divided into 24 time zones, each roughly 15 degrees of longitude wide. As you move east, time increases. As you move west, time decreases.
UTC (Coordinated Universal Time) is the primary time standard by which the world regulates clocks. All time zones are defined by their offset from UTC:
| Offset | Time Zone Name | Major Cities |
|---|---|---|
| UTC-12 | Baker Island Time | Uninhabited |
| UTC-11 | Samoa Standard Time | Pago Pago |
| UTC-10 | Hawaii-Aleutian Standard Time | Honolulu |
| UTC-9 | Alaska Standard Time | Anchorage |
| UTC-8 | Pacific Standard Time (PST) | Los Angeles, Vancouver, Seattle |
| UTC-7 | Mountain Standard Time (MST) | Denver, Phoenix, Calgary |
| UTC-6 | Central Standard Time (CST) | Chicago, Mexico City, Dallas |
| UTC-5 | Eastern Standard Time (EST) | New York, Toronto, Miami |
| UTC-4 | Atlantic Standard Time (AST) | Halifax, San Juan |
| UTC-3 | Brasilia Time | São Paulo, Buenos Aires |
| UTC+0 | Greenwich Mean Time (GMT) | London, Lisbon, Accra |
| UTC+1 | Central European Time (CET) | Paris, Berlin, Rome, Madrid |
| UTC+2 | Eastern European Time (EET) | Cairo, Athens, Helsinki |
| UTC+3 | Arabia Standard Time (AST) | Moscow, Istanbul, Nairobi |
| UTC+4 | Gulf Standard Time (GST) | Dubai, Abu Dhabi, Baku |
| UTC+5 | Pakistan Standard Time (PKT) | Karachi, Lahore, Islamabad |
| UTC+5:30 | India Standard Time (IST) | Mumbai, Delhi, Bangalore |
| UTC+6 | Bangladesh Standard Time | Dhaka, Almaty |
| UTC+7 | Indochina Time (ICT) | Bangkok, Hanoi, Jakarta |
| UTC+8 | China Standard Time (CST) | Beijing, Singapore, Perth |
| UTC+9 | Japan Standard Time (JST) | Tokyo, Seoul |
| UTC+10 | Australian Eastern Time (AET) | Sydney, Melbourne, Guam |
| UTC+12 | New Zealand Standard Time | Auckland, Suva |
Use our Timezone Converter to convert time between any two cities or time zones instantly.
UTC vs GMT: What’s the Difference?
In everyday use, UTC and GMT are interchangeable. Technically:
- GMT is a time zone (used by the UK and some African countries)
- UTC is a time standard (not a time zone)
Both show the same time. The difference matters only for scientific purposes.
When you see a time like “14:00 UTC,” that’s the same as “14:00 GMT” for practical purposes.
Time Zone Conversion for Major Cities
North America
| City | Time Zone | UTC Offset (Standard) | UTC Offset (Daylight) |
|---|---|---|---|
| New York | EST/EDT | UTC-5 | UTC-4 |
| Chicago | CST/CDT | UTC-6 | UTC-5 |
| Denver | MST/MDT | UTC-7 | UTC-6 |
| Los Angeles | PST/PDT | UTC-8 | UTC-7 |
| Toronto | EST/EDT | UTC-5 | UTC-4 |
| Vancouver | PST/PDT | UTC-8 | UTC-7 |
| Mexico City | CST | UTC-6 | UTC-5 |
Europe
| City | Time Zone | UTC Offset (Standard) | UTC Offset (Daylight) |
|---|---|---|---|
| London | GMT/BST | UTC+0 | UTC+1 |
| Paris | CET/CEST | UTC+1 | UTC+2 |
| Berlin | CET/CEST | UTC+1 | UTC+2 |
| Rome | CET/CEST | UTC+1 | UTC+2 |
| Madrid | CET/CEST | UTC+1 | UTC+2 |
| Moscow | MSK | UTC+3 | UTC+3 (no DST) |
| Istanbul | TRT | UTC+3 | UTC+3 (no DST) |
Asia & Middle East
| City | Time Zone | UTC Offset | DST? |
|---|---|---|---|
| Dubai | GST | UTC+4 | No |
| Doha | AST | UTC+3 | No |
| Riyadh | AST | UTC+3 | No |
| Mumbai | IST | UTC+5:30 | No |
| Singapore | SGT | UTC+8 | No |
| Tokyo | JST | UTC+9 | No |
| Beijing | CST | UTC+8 | No |
| Seoul | KST | UTC+9 | No |
| Bangkok | ICT | UTC+7 | No |
| Hong Kong | HKT | UTC+8 | No |
Middle East & Africa
| City | Time Zone | UTC Offset | DST? |
|---|---|---|---|
| Dubai | GST | UTC+4 | No |
| Doha | AST | UTC+3 | No |
| Riyadh | AST | UTC+3 | No |
| Abu Dhabi | GST | UTC+4 | No |
| Kuwait City | AST | UTC+3 | No |
| Cairo | EET | UTC+2 | Yes (starts April) |
| Johannesburg | SAST | UTC+2 | No |
| Lagos | WAT | UTC+1 | No |
| Nairobi | EAT | UTC+3 | No |
Australia & Pacific
| City | Time Zone | UTC Offset (Standard) | UTC Offset (Daylight) |
|---|---|---|---|
| Sydney | AEST/AEDT | UTC+10 | UTC+11 |
| Melbourne | AEST/AEDT | UTC+10 | UTC+11 |
| Brisbane | AEST | UTC+10 | UTC+10 (no DST) |
| Perth | AWST | UTC+8 | UTC+8 (no DST) |
| Auckland | NZST/NZDT | UTC+12 | UTC+13 |
| Fiji | FJT | UTC+12 | UTC+13 |
Common Time Zone Conversions
Convert EST to GMT/UTC
| EST | GMT (UTC) | Example Location |
|---|---|---|
| 6 AM | 11 AM | New York morning → London afternoon |
| 9 AM | 2 PM | New York late morning → London evening |
| 12 PM | 5 PM | New York noon → London late afternoon |
| 3 PM | 8 PM | New York afternoon → London night |
| 6 PM | 11 PM | New York evening → London late night |
| 9 PM | 2 AM (next day) | New York night → London early morning |
Convert PST to GMT/UTC
| PST | GMT (UTC) | Example Location |
|---|---|---|
| 6 AM | 2 PM | LA morning → London afternoon |
| 9 AM | 5 PM | LA morning → London late afternoon |
| 12 PM | 8 PM | LA noon → London evening |
| 3 PM | 11 PM | LA afternoon → London night |
| 6 PM | 2 AM (next day) | LA evening → London early morning |
Convert Dubai (UTC+4) to Major Cities
| Dubai | London (UTC+0/+1) | New York (UTC-5/-4) | Tokyo (UTC+9) | Sydney (UTC+10/+11) |
|---|---|---|---|---|
| 8 AM | 4 AM (5 AM BST) | 11 PM (previous) | 1 PM | 2 PM (3 PM AEDT) |
| 12 PM | 8 AM (9 AM BST) | 3 AM | 5 PM | 6 PM (7 PM AEDT) |
| 4 PM | 12 PM (1 PM BST) | 7 AM | 9 PM | 10 PM (11 PM AEDT) |
| 8 PM | 4 PM (5 PM BST) | 11 AM | 1 AM (next) | 2 AM (3 AM AEDT) |
Convert London (GMT/BST) to Major Cities
| London | New York (UTC-5/-4) | Dubai (UTC+4) | Singapore (UTC+8) | Sydney (UTC+10/+11) |
|---|---|---|---|---|
| 8 AM GMT | 3 AM EST | 12 PM | 4 PM | 6 PM AEST |
| 12 PM GMT | 7 AM EST | 4 PM | 8 PM | 10 PM AEST |
| 9 AM BST | 4 AM EDT | 12 PM | 4 PM | 6 PM (7 PM AEDT) |
| 5 PM BST | 12 PM EDT | 8 PM | 12 AM (next) | 2 AM (3 AM AEDT) |
Daylight Saving Time (DST)
Which Countries Observe DST?
| Region | Observes DST | DST Period |
|---|---|---|
| United States | Yes (most states) | March-November |
| Canada | Yes (most provinces) | March-November |
| Europe | Yes (all EU) | Last Sunday March - Last Sunday October |
| UK | Yes | Last Sunday March - Last Sunday October |
| Australia | Varies by state | October-April |
| New Zealand | Yes | September-April |
| Middle East | Mostly no | — |
| India | No | — |
| China | No | — |
| Japan | No | — |
DST Start and End Dates (2026)
| Region | DST Starts | DST Ends |
|---|---|---|
| United States | Sunday, March 8 | Sunday, November 1 |
| Canada | Sunday, March 8 | Sunday, November 1 |
| Europe | Sunday, March 29 | Sunday, October 25 |
| United Kingdom | Sunday, March 29 | Sunday, October 25 |
| Australia (states with DST) | Sunday, October 4 | Sunday, April 5 |
| New Zealand | Sunday, September 27 | Sunday, April 5 |
The DST Trap
In March, clocks spring forward (1 hour lost). In November, clocks fall back (1 hour gained). This means:
- March to November: US East Coast is UTC-4 (EDT), not UTC-5 (EST)
- November to March: US East Coast is UTC-5 (EST), not UTC-4 (EDT)
- UK: UTC+1 in summer (BST), UTC+0 in winter (GMT)
Always check whether DST is active before scheduling meetings.
Time Zones with Unusual Offsets
Not all time zones are whole hours offset from UTC. Some are 30 or 45 minutes off:
| Offset | Location | Why? |
|---|---|---|
| UTC+5:30 | India | Half-hour zone (established 1906) |
| UTC+5:45 | Nepal | 15 minutes ahead of India |
| UTC+6:30 | Myanmar, Cocos Islands | Half-hour zone |
| UTC+8:45 | Eucla (Australia) | 45-minute zone |
| UTC+9:30 | South Australia, Darwin | Half-hour zone |
| UTC+12:45 | Chatham Islands (NZ) | 45 minutes ahead of NZ |
| UTC-3:30 | Newfoundland (Canada) | Half-hour zone |
| UTC-4:30 | Venezuela | Was UTC-4:30 until 2016 |
Time Zone Converter Tool
Our Timezone Converter lets you:
- Convert time between any two cities
- See current time in 100+ major cities
- Compare multiple time zones at once
- Account for DST automatically
Practical Time Zone Scenarios
Scenario 1: Scheduling a Global Team Meeting
You’re in Dubai (UTC+4). Your team is in London (UTC+1 BST), New York (UTC-4 EDT), and Singapore (UTC+8).
Best overlapping time: 2 PM Dubai = 11 AM London = 6 AM New York = 6 PM Singapore
This gives everyone reasonable hours — London is mid-morning, Singapore is evening, New York is early morning.
Scenario 2: Flight Arrival Time
You fly from Doha to New York. The flight departs Doha at 8 AM and takes 14 hours. What time do you land in New York?
Doha is UTC+3. New York is UTC-4 (EDT in summer). That’s a 7-hour difference.
8 AM + 14 hours = 10 PM Doha time. Subtract 7 hours = 3 PM New York time.
Scenario 3: Calling Family
You’re in Los Angeles (PST, UTC-7 in summer). Your family is in Mumbai (IST, UTC+5:30).
Difference: 12.5 hours. If it’s 9 AM in LA, it’s 9:30 PM in Mumbai. Best time to call: your morning = their evening.
Scenario 4: Remote Work Across Time Zones
You manage a team spread across 4 time zones. Set these ground rules:
- Core overlap hours: 2-3 hours where everyone is available
- Async-first communication: Use Slack/Teams with clear written updates
- Meeting rotation: Alternate early and late meetings so no one always suffers
- Shared calendar: Display everyone’s time zone for easy scheduling
Tips for Working Across Time Zones
1. Use a World Clock
Keep a world clock widget showing your most-used time zones. Most operating systems let you add multiple clocks.
2. Standardise on UTC for Planning
When scheduling across time zones, communicate all times in UTC. Each person converts to their local time. This eliminates confusion.
3. Respect Non-Work Hours
Just because it’s your 10 AM doesn’t mean it’s theirs. Be mindful of sending messages during their late evening or overnight.
4. Use Scheduling Tools
- Calendly / Cal.com: Shows your availability in the invitee’s time zone
- World Time Buddy: Side-by-side time zone comparison
- Every Time Zone: Visual grid of time zones worldwide
- Google Calendar: Built-in time zone support for events
5. Document Time Zones in Your Profile
Include your time zone in your email signature, Slack profile, and meeting invites. This helps everyone know when you’re available.
FAQ
What is the largest time zone difference? The maximum possible time difference between any two points on Earth is 26 hours. The Line Islands (Kiribati, UTC+14) are 26 hours ahead of Baker Island (US, UTC-12).
How many time zones are there? More than 24. While the concept divides the Earth into 24 zones, fractional offsets (like India’s UTC+5:30) bring the total to about 40 time zones worldwide.
What country has the most time zones? France, with 12 time zones (including overseas territories). The US has 11 (including territories). Russia has 11.
Why does China have only one time zone? Despite spanning five geographical time zones, China has used a single time zone (UTC+8) since 1949 for national unity. This means the sun rises as late as 10 AM in western China during winter.
What time zone is used for aviation? Aviation uses Zulu Time (Z), which is the same as UTC. All flight plans, weather reports, and air traffic control communications use Zulu Time to avoid confusion across jurisdictions.
Does every country observe DST? No. Only about 70 countries observe DST. Most countries near the equator don’t change their clocks. India, China, Japan, and most of Africa and the Middle East do not observe DST.
What happens when time zones change politically? Countries occasionally change time zones. Samoa skipped December 30, 2011 to move from UTC-11 to UTC+13 for business reasons. Venezuela changed its offset multiple times for political reasons. Always verify time zone data for current accuracy.
How do I calculate time zone differences manually? Convert both times to UTC, then compare. For example: New York (UTC-5) and Dubai (UTC+4). The difference is 9 hours (5 + 4). When it’s 12 PM in New York (17:00 UTC), it’s 9 PM in Dubai (21:00 UTC).
What’s the best way to avoid time zone confusion? Schedule everything in UTC. Let each person convert to their local time. Use a timezone converter tool for quick checks.
Do programmers use UTC? Yes. Most backend systems and databases store times in UTC and convert to local time only for display. This prevents bugs caused by time zone and DST changes.
Convert time between any two cities instantly with FreeToolz’s Timezone Converter — free, no signup required.